TROUBLESHOOTING FOR NOISE


AUDIO UNIT


The noise is generated during the engine run.
caution
  • Check that no noise of external origin is present. Because the signal reception becomes poor indoors, check in the open air. If this check is neglected, the source of noise cannot be determined, resulting in a false recognition. Therefore, be sure to perform this check.
  • When implementing the noise prevention, start the prevention from the object causing the strongest noise.
  • Check that the audio main body and others are securely grounded.
Noise types
( ) indicates the sound type.
 Situation
 Cause
 Countermeasure
AM,FM, LW, MW:
(Crack, tapping, rattle, plash)
  • When the engine speed is increased, the scratch noise becomes faster and the sound volume decreases.
  • When the ignition switch is turned to ACC, the noise disappears.
  • Radiation noise caused mainly by the spark plug
  • Noise wraparound

 Check or replace the earth cable earth bolt. (Refer to Figure 1).
AM,FM, LW, MW:
Wiper motor noise (hum, distorted hum)
Synchronised with the wiper movement, and also becomes faster when wiper movement is sped up. When the wiper is stopped, the noise also stops.
 Caused by the sparks generated by the wiper motor brush.
 Replace the wiper motor.
Noise from other electrical equipment
 -
 The noise may be generated when the electrical equipment become old.
 Repair or replace the electrical equipment.
Static electricity (cracking, popping)
 No noise is generated when the vehicle comes to a complete stop.
 The parts or wiring move for some reason, and cause the noise by contacting against the body metal parts.
 Return the parts and wiring to the normal positions.
Various types of noise are generated in various parts of the body.
 Caused by the looseness between the body and the hood, tailgate, bumper, exhaust pipe and muffler, suspension, or others.
 Securely tighten the mounting bolts of each part.
note For trouble symptoms other than the noise, perform the following troubleshooting procedures. Refer to .